MIMO-OFDM系統之鏈路自適應演算法

Abstract

Abstract Multiple Input Multiple Output (MIMO) systems have been researched and developed in wireless communication systems. MIMO systems can increase systems capacity and link level quality. The purpose of this thesis is to analyze multiple antenna techniques and MIMO with the main focus on estimation and detection for MIMO channels. Firstly the thesis will introduce the basic principles of the all popular multiple antenna techniques. Next we will examine MIMO estimation techniques including linear and non linear or from simple to complex techniques, including linear estimate Zero Forcing (ZF), Minimum Mean Squared Error (MMSE), Nonlinear VBLAST, SVD, MRC and Alumouti code. The remainder of the thesis will focus on VBLAST architecture and which algorithm can achieve the highest spectral efficiency in multiple-input multiple-output (MIMO) systems due to the multiplexing and diversity over the space domain Base benefit of each technique. We have provided a combination of techniques which can reach simple implementation and achieve about performance. In our first test case we combine VBLAST with ZF and MRC and the second case presented, we combined VBLAST with ALAMOUTI and ZF. In this thesis in addition to using ZF we also analyzed the performance when using minimum mean square error (MMSE) and parallel interference cancellation (PIC) detection technologies Keywords: MIMO, OFDM, ZF, MMSE, MRC, VBLAST, ALAMOUTI

摘要 為了提高系統容量和鏈路品質，多輸入多輸出（Multiple Input Multiple Output, MIMO）系統在無線通訊上持續的被研究與開發。本文的目的是針對MIMO通道的估計和檢測去分析多天線技術和MIMO。首先，本文將介紹所有常見多天線技術的基本原理。然後，我們將檢驗MIMO估計技術，包括線性和非線性或從簡單到複雜的技術，包括線性估計零強制（Zero Forcing, ZF）、最小均方誤差（Minimum Mean Squared Error, MMSE）、非線性V-BLAST、SVD、MRC和ALAMOUTI編碼。本文將集中在V-BLAST架構下的多輸入多輸出演算法，藉由每個技術在空間多工和空間分集的效益，實現最高頻譜效率。我們提供一個容易實現兼具效能的整合技術。 在我們的第一個測試情況下，結合了VBLAST與ZF和MRC。在第二種情況，我們結合V-BLAST與ALAMOUTI和ZF。在本文中，除了使用ZF我們還分析最小均方誤差和並行干擾消除（parallel interference cancellation, PIC）檢測技術的性能。